Lubrication for pneumatic tools



Jan. 28, 1964 E. B. BURNETT LUBRICATION FOR PNEUMATIC TOOLS Filed July 5, 1960 'INVENTOR ELMER B. BURNETT ATT RN EY HIS United States Patent 3,119,456 LUBRICATION FUR PNEUMATIC TOOLS Elmer B. Burnett, Monroeton, Pa, assignor to Ingersoll- Rand Company, New York, N.Y., a corporation of New Jersey Filed July 5, 1968, Ser. No. 40,928 6 Claims. (Cl. 173-93) This invention relates to pneumatic rotary tools.

The various means used to date for lubricating the parts, other than motor parts, have been limited in their success for the following reasons.

Lubrication through a grease fitting in the hammercase. This means, putting all the grease on top of or on the outside of the gear and other mechanism. In operation, centrifugal force throws this grease against the gear case where it is ineffective. With this method, grease will not reach the internal parts.

Oil bath lubrication where the mechanism is run in oil does a good job of lubricating, but presents problems in sealing the mechanism against leakage. These seals have to be frequently replaced causing high maintenance cost.

Lubrication by disassembly. This provides thorough lubrication, but also necessitates high maintenance cost in that the tool has to be completely disassembled every time it needs lubrication. The advantages of the method of this invention are that the lubricant is fed into the center of the mechanism and lubricates all the parts as it moves up through the mechanism. At the same time it allows the tool to be externally loaded with lubricant as becomes necessary.

It is accordingly an object of this invention to provide a pneumatic rotary hammer tool in which the various parts are provided with suitable lubricants for the duties they undergo.

It is another object of this invention to provide such a tool in which the parts are readily accessible for insertion, and cleaning, and replacement.

Other objects of the invention will be in part obvious and in part pointed out hereinafter.

The drawing illustrates the invention in a preferred embodiment and includes a side elevation of a hammer tool constructed in accordance with the practice of the invention, parts being in section to show the internal mechanism.

Referring to the drawing, the tool includes a motor casing 10 in this instance formed integrally with a handle portion 12. Motor casing 18 is machined from one end forming a large opening thereat normally closed by a cap 100, the resulting interior cavity being cylindrical for insertion of a pneumatic motor 14. The motor 14 includes a cylinder portion or motor body 16 having front and rear plates 18 and 28 for supporting a rotary drive portion rotor 22 having sliding vanes 24 all of which constitute the usual elements of multiple vane type rotary motor.

The rotary drive portion 22 is suitably journaled, as at 26 and 28, in end plates 18 and 20, respectively. Motor 14 is adapted to drive a rotary hammer mechanism 30 housed within a hammer casing 32 sealingly attached by bolts (not shown), or any other well known conventional means, to end 34 of motor casing 10. The hammer mechanism 30 is similar in construction and operation to that shown and described in US. Patent 2,881,884 that was granted April 14, 1959, to L. A. Amtsberg. It should be understood, however, that this impact mechanism is for illustration of a general class of apparatus and there is no intent to define the limits of the present invention thereby. Hammer casing 32 has a nose portion 36 with a liner type flanged sleeve bearing 38 through which extends an anvil member 40 adapted to receive intermittent blows from hammer mechanism 30. Anvil 40 terminates 3,119,456 Patented Jan. 28, 1964 ice in a wrench socket supporting end 42 having a retaining pin 44 of any desired form.

Hammer mechanism 30 is provided with a hollow hammer member 46 fluted or having splines 48 for coupling with a fluted end or splined shaft 50 of rotary drive portion 22. A roller 52 is mounted on a transverse pin 54 carried in hammer 46 and is adapted to actuate a cam 56 in a reciprocating fashion on a rearwardly extending pin 58 set in bore 60 formed axially in anvil 40. The hammer mechanism 30 and anvil 40 are substantially as shown, described and claimed in US. patent application S.N. 204,461, filed by .T. S. Vaughn on June 22, 1962 (a continuation of US. patent application 749,476, filed July 18, 1958) and assigned to the same assignee as is the present application. It should be understood, however, that this hammer and anvil arrangement is for illustration purposes only and is not intended to define the limits of the present invention. Any comparable hammer and anvil may be substituted for the foregoing.

While cam 56 is held against rotation with respect to pin 58 by a spline 62, it can move axially thereon against the force of a compression spring 64 that encircles pin 58. A washer 66 is disposed between adjacent ends of cam 56 and spring 64 while the other end of spring 64 seats on the head of pin 58 in the bottom of bore 60 in anvil 40. Thus, washer 66 provides a seat whose thickness determines the amount of compression of spring 64 relative to the head of pin 58 when cam 56 is in its rearmost position. As shown, the diameter of washer 66 is larger than that of bore 60 and will contact the end of anvil 40 to limit forward axial movement of cam 56 and thereby limit axial compression of spring 64 by such axial movement of the cam.

Hammer mechanism 30 has a dog member 68 rotatably mounted on cam 56 for rotation with hammer member 46 and for axial movement with cam 56 relative tohammer member 46. Thus, as hammer mechanism 30 is rotated by motor 14, roller 52 rides on the ramp surface of cam 56 urging the cam, with the action of spring 64, to reciprocate axially on pin 58. Dog member 68 thus rotates as part of the hammer mechanism 30, and is simultaneously reciprocated by the reciprocal action of cam 56. It can now be readily understood that spring 64 also has a principal function of urging cam 56, with dog 68, rearwardly into engagement with roller 52.

It will thus be seen that relative rotation of hammer mechanism 30 with respect to anvil 40 imparts an intermittent axially reciprocating motion of dog member 68 forwardly under the force of cam 56 and rearwardly by expansion of compression spring 64. Dog member 68 has a jaw or lug '70 adapted to impact a jaw or lug 72 of anvil 40 each time the dog 68 is moved axially forwardly by cam 56 to progressively rotate anvil 40 with each impact.

Endwise motion of pin 58 is undesirable and for this purpose a thrust member 76 mounted on the pilot end 78 of pin 58 presses against a shoulder 80 formed in hammer 46.

The actual working of the parts of the hammer mech anism is described rather summarily as it does not directly involve the present invention but is mentioned for the purpose of indicating that the hammer mechanism 30 involves heavy bearing loads subject to shocks requiring relatively heavy lubricant films as compared with the motor portion of the mechanism which preferably is lubricated by a light oil.

This invention is specifically directed to means of storing grease lubricant and to feed the grease to the hammer mechanism. To this end, the open end of motor casing 10 is closed by a hollow cap member providing a cavity 102 of considerable capacity, one wall of the cavity being the end plate 20. When secured in place by suitable screws 104 end cap 100 bears against end To provide communication from cavity 102 to the interior of hammer 46, rotary drive portion 22 is provided with a conducting passage, in this instance an axial bore 112 extending lengthwise through the portion 22 and terminating at the thrust member 76. The small holes 114, in the thrust member 76, act as a metering device in that the number and size of these holes are so designed to allow the proper amount of lubricant flow from the storage chamber to the hammer mechanism.

A vent for the casings, both the forward part of motor casing and hammer casing 32, is provided by way of an air passage 107 allowing air leaking between the front endplate 18 and the rotor 22 to be bled off through the motor exhaust cavity 109. This also allows a portion of the air in the hammer case 32 to bleed back on the outside of the hammer 30 through the hammer bearing 120, past the spring element 106, and into this air passage. No such air bleed passage is provided through the casing 10 rearwardly of the motor 14, thus, air leakage past the rear plate will create a pressure diiference across motor 14 that is greater in the lubricant cavity 102 than is derived in the hammer case 32 during tool operation. This pressure difference causes air and grease to flow through bore 112 and into the hammer case 32.

For charging the cavity 102, a suitable grease coupling 122 is provided in cap 100 in line with bore 112. The coupling 122 is so positioned to insure that when grease is inserted into the cavity 102 that it will be surely introduced into bore 112. Furthermore if grease should become hardened, grease coupling 122 may be removed and wire or another suitable implement poked into the bore 112 to loosen up the grease.

This tool is of course provided at its handle portion 12' with a suitable coupling and interior passages (not shown) to provide compressed air to drive motor 10 as they are well known in the art, and are not of pertinence in connection with the invention. It may be mentioned however that it would be expected that lubricating oil for motor 14 would be introduced either in the air supply or in any other well known manner.

The throttle for controlling the flow of compressed air to the tool is indicated at 130, and further, a suitable reversing control is indicated at 132,. no details are described as being irrelevant in this connection.

Thus by the above construction are accomplished, among others, the objects hereinbefore referred to.

I claim:

1. A rotary tool comprising:

(a) a casing closed at the rear end thereof;

(b) an anvil rotatably supported in the front end of the casing;

(c) a hammer mechanism rotatable in the casing being operatively associated with the anvil to intermittently strike and rotate said anvil when said hammer mechanism is rotated;

(01) a motor disposed in the casing having a rotor connected to the hammer mechanism;

(e) the rotor having an axial bore therethrough in communication with the space within the casing to provide a storage space for a lubricant and a flow path for such stored lubricant to the hammer mechanism; and

(f) the casing having means adapted to receive lubricant to be stored in the axial bore.

2. A rotary tool comprising:

(a) a casing including a removable cover portion to close the rear end thereof;

(b) an anvil rotatably supported in the front end of the casing;

(c) a hammer mechanism rotatable in the casing being operatively associated with the anvil to intermittently strike and rotate said anvil when said hammer mechanism is rotated;

(d) a motor disposed in the casing having a rotor connected to the hammer mechanism;

(e) the cover portion retaining the motor in the casing and having a recess to provide a space adjacent the rear end of the rotor;

(f) the rotor having an axial bore therethrough in communication at its rear end with the recess in the cover portion which together provide a storage space for a lubricant and being in communication at its front end with the space in the casing forwardly of the motor to provide a flow path for stored lubricant to the hammer mechanism; and

g) the cover portion having a filler coupling in alinement with the axial bore being adapted to receive a lubricant to be stored in the storage space.

3. A rotary tool in accordance with claim 2, and

(a) the hammer mechanism having metering orifices therethrough in communication with the axial bore to provide a how path for lubricant to the anvil.

4. A rotary tool comprising:

(a) a casing closed at the rear end thereof;

(b) an anvil rotatably supported in the front end of.

the casing; (c) a hammer mechanism rotatable in the casing being operatively associated with the anvil to intermittently strike and rotate said anvil when said hammer mechanism is rotated;

(d) a pressure fluid driven motor disposed in the casing having a rotor connected at its front end to the hammer mechanism, and having openings in its ends for the escape of leakage of pressure fluid therefrom to the space within the casing forwardly and rear Wardly of the motor;

(e) the rotor having an axial bore therethrough in communication at its ends with the space in the casing forwardly and rearwardly of the motor to provide a storage space for a lubricant and a flow path for such stored lubricant to the hammer mechanism; and

(f) the casing having means adapted to receive lubricant to be. stored in the axial bore, and having vent means forwardly of the motor for leakage of pressure fluid to cause a pressure differential across the motor to feed stored lubricant to the hammer mechanism.

5. A rotary tool comprising:

(a) a casing including a removable cover portion to close the rear end thereof;

(b) an anvil rotatably supported in the front end of the casing;

(c) a hammer mechanism rotatable in the casing being operatively associated with the anvil to intermittently strike and rotate said anvil when said hammer mechanism is rotated;

(d) a pressure fluid driven motor disposed in the casing having a rotor connected at its front end to the hammer mechanism;

(e) the cover portion retaining the motor in the casing and having a recess to provide a space in the casing rearwardly of the rotor;

( f) the motor having openings in its ends for the escape of pressure fluid therefrom into the recess of the cover portion and into the casing forwardly of the motor;

(g) the rotor having an axial bore therethrough in communication at its rear end with the recess in the cover portion which together provide a storage space for a lubricant and being in communication at its. front end with the space in the casing forwardly of the motor to provide a how path for stored lubricant to the hamrner mechanism;

(It) the cover portion having a filler coupling in alinement with the axial bore being adapted to receive lubricant to be stored in the storage space; and

(i) the casing having vent means forwardly of the motor for leakage of pressure fluid to cause a pressure differential across the motor to feed stored lubricant to the hammer mechanism.

6. A rotary tool in accordance with claim 5, and

(a) the hammer mechanism having metering orifices therethrough in communication with the axial bore to provide a flow path for lubricant to the anvil.

References Cited in the file of this patent UNITED STATES PATENTS Brush Aug. 2, 1921 Hill Apr. 27, 1954 Maurer Mar. 12, 1957 Toth Mar. 1, 1960 Roggenburk Aug. 2, 1960 Roggenburk Nov. 29, 1960 

1. A ROTARY TOOL COMPRISING: (A) A CASING CLOSED AT THE REAR END THEREOF; (B) AN ANVIL ROTATABLY SUPPORTED IN THE FRONT END OF THE CASING; (C) A HAMMER MECHANISM ROTATABLE IN THE CASING BEING OPERATIVELY ASSOCIATED WITH THE ANVIL TO INTERMITTENTLY STRIKE AND ROTATE SAID ANVIL WHEN SAID HAMMER MECHANISM IS ROTATED; (D) A MOTOR DISPOSED IN THE CASING HAVING A ROTOR CONNECTED TO THE HAMMER MECHANISM; (E) THE ROTOR HAVING AN AXIAL BORE THERETHROUGH IN COMMUNICATION WITH THE SPACE WITHIN THE CASING TO PROVIDE A STORAGE SPACE FOR A LUBRICANT AND A FLOW PATH FOR SUCH STORED LUBRICANT TO THE HAMMER MECHANISM; AND (F) THE CASING HAVING MEANS ADAPTED TO RECEIVE LUBRICANT TO BE STORED IN THE AXIAL BORE. 